A FORTRAN Computer Program for Calculating the Prolate Spheroidal Angular Functions of the First Kind
Abstract
The Helmholtz wave equation (sq del + sq K) psi = 0 is separable in prolate spheroidal coordinates (eta, xi, psi) with the solution psi = R(c, xi) S(c, eta)Phi(phi). Here c = ka/2, where a is the interfocal distance. A computer program called PANGFN has been developed to numerically evaluate in double- precision arithmetic the angular function of the first kind S(ml)(1) (c, eta) for any desired values of c, m, l, and the argument Theta = ARCCCOS(eta). The program is written in universal FORTRAN and should run on any computer that accepts this language. Special techniques are used to avoid overflow and underflow problems. By the use of logarithms, PANGFN can compute the angular function even when its value exceeds the exponent range of the computer. This report describes the principle features of PANGFN. Included are discussions of the significant FORTRAN variable names, dimensions and storage, parameter input, parameter ranges, computational procedure, computation time, printed output, and accuracy of the results. A sample output and a computer listing of LINPRO are attached as appendices.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 13, 1981
- Accession Number
- ADA095922
Entities
People
- A. L. Van Buren
- B. J. Patz
Organizations
- United States Naval Research Laboratory